Guidewires for performing image guided procedures

ABSTRACT

Guidewires and methods useable in conjunction with image guidance systems to facilitate performance of diagnostic or therapeutic tasks at locations within the bodies of human or animal subjects.

RELATED APPLICATION

This application is a continuation in part of U.S. patent applicationSer. No. 11/16,118 entitled Methods and Devices for PerformingProcedures Within the Ear, Nose, Throat and Paranasal Sinuses filed Apr.26, 2005, which is a continuation in part of 1) U.S. patent ApplicationSer. No. 10/829,917 entitled “Devices, Systems and Methods forDiagnosing and Treating Sinusitis and Other Disorders of the Ears, Noseand/or Throat” filed on Apr. 21, 2004, 2) U.S. patent application Ser.No. 10/912,578 entitled “Implantable Device and Methods for DeliveringDrugs and Other Substances to Treat Sinusitis and Other Disorders” filedon Aug. 4, 2004, 3) U.S. patent application Ser. No. 10/944,270 entitled“Apparatus and Methods for Dilating and Modifying Ostia of ParanasalSinuses and Other Intranasal or Paranasal Structures” filed on Sep. 17,2004 and 4) U.S. patent application Ser. No. 11/037,548 entitled“Devices, Systems and Methods For Treating Disorders of the Ear, Noseand Throat” filed Jan. 18, 2005, the entireties of each such parentapplication being expressly incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to methods and devices formedical treatment and more particularly to guidewires adapted for usewith electromagnetic image guidance systems and their method ofmanufacture and use.

BACKGROUND OF THE INVENTION

Image-guided surgery (IGS) is a technique wherein a computer is used toobtain a real-time correlation of the location of an instrument that hasbeen inserted into a patient's body to a set of preoperatively obtainedimages (e.g., a CT or MRI scan) so as to superimpose the currentlocation of the instrument on the preoperatively obtained images. In atypical IGS procedure, a digital tomographic scan (e.g., CT or MRI) ofthe operative field is obtained prior to surgery. A specially programmedcomputer is then used to convert the digital tomographic scan data intoa digital map. During surgery, special instruments having sensors (e.g.,electromagnetic coils that emit electromagnetic fields) mounted thereonare used to perform the procedure while the sensors send data to thecomputer indicating the current position of each surgical instrument.The computer correlates the data it receives from the instrument-mountedsensors with the digital map that was created from the preoperativetomographic scan. The tomographic scan images are displayed on a videomonitor along with an indicator (e.g., cross hairs or an illuminateddot) showing the real time position of each surgical instrument relativeto the anatomical structures shown in the scan images. In this manner,the surgeon is able to know the precise position of each sensor-equippedinstrument without being able to actually view that instrument at itscurrent location within the body.

Examples of commercially available electromagnetic IGS systems that havebeen used in ENT and sinus surgery include the ENTrak Plus™ andInstaTrak ENT™ systems available from GE Medical Systems, Salt LakeCity, Utah. Other examples of electromagnetic image guidance systemsthat may be modified for use in accordance with the present inventioninclude but are not limited to those available from Surgical NavigationTechnologies, Inc., Louisville, Colorado, Biosense-Webster, Inc.,Diamond Bar, Calif. and Calypso Medical Technologies, Inc., Seattle,Wash.

When applied to functional endoscopic sinus surgery (FESS) the use ofimage guidance systems allows the surgeon to achieve more precisemovement and positioning of the surgical instruments than can beachieved by viewing through an endoscope alone. This is so because atypical endoscopic image is a spatially limited, 2 dimensional,line-of-sight view. The use of image guidance systems provides a realtime, 3 dimensional view of all of the anatomy surrounding the operativefield, not just that which is actually visible in the spatially limited,2 dimensional, direct line-of-sight endoscopic view. As a result, imageguidance systems are frequently used during performance of FESS,especially in cases where normal anatomical landmarks are not present,in revision sinus surgeries or wherein the surgery is performed to treatdisease that abuts the skull base extends into the frontal or sphenoidsinus, dehiscent lamina papyracea and/or orbital pathology.

Additionally, a procedure for balloon dilation of the ostia of paranasalsinuses has been developed, wherein a guidewire is advanced into adiseased paranasal sinus and a balloon catheter is then advanced overthe guidewire to dilate the ostium of that paranasal sinus, therebyimproving drainage from the diseased sinus (Balloon Sinuplasty™ system,Acclarent, Inc., Menlo Park, Calif.). Parent application Ser. No.11/16,118 describes a variety of sensor equipped devices includingsensor equipped guidewires that are useable in performance of theprocedure using Balloon Sinuplasty™ tools under image guidance inconjunction with an IGS system.

There remains a need in the art for the development of improved sensorequipped instruments and devices for use in IGS procedures.

SUMMARY OF THE INVENTION

The present invention provides guidewires having sensors (e.g.,electromagnetic coils that detect or emit electromagnetic energy andradiofrequency devices that emit or detect radiofrequency energy likeantennas) and removable proximal hubs that interface with an IGS system.The guidewires of one embodiment of the present invention are useable inconjunction with electromagnetic IGS systems such that the IGS systemmay be used to track the real time position of the guidewire within thebody of a human or animal subject.

In accordance with one embodiment of the present Invention, there isprovided a guidewire device for use with an image guidance surgerysystem. Such guidewire device generally comprises a) an elongateguidewire shaft having a proximal end and a distal end, b) a sensorlocated on or in said shaft, such sensor being operative to emit energythat may be used by an image guidance system for real time determinationof the location of the sensor within a subject's body, c) firstelectrical contacts located on the shaft at or near its proximal end, d)wires extending between the sensor and the contacts and e) a connectorhub member that is disposable on and removable from the guidewire shaft,such hub member having second electrical contacts that electricallycouple to the first electrical contacts on the guidewire when the hubmember is disposed on said guidewire shaft. In this manner, the hubmember facilitates delivery of current to the sensor and the sensoremits a field which is used by the image guidance system to ascertainthe position of the guidewire within the subject's body. After theguidewire has been advanced to its intended position, the hub member isremoved from the guidewire, thereby allowing other devices (e.g.,catheters and the like) to be advanced over the guidewire and used toperform diagnostic or therapeutic task(s). In some embodiments, theguidewire may be less than 110 centimeters in length (e.g.,approximately 100 centimeters) and may be transnasally insertable to alocation within the ear, nose, throat or paranasal sinus of the subject.In some embodiments, a polymer layer (e.g., heat shrunk polymer film)may be formed on a portion of the guidewire to facilitate grasping ofthe guidewire during use but such polymer layer may cover less than theentire length of the guidewire.

Further in accordance with the invention, there is provided a method forusing an image guidance system to determine the location of a guidewirewithin the body of a human or animal subject, such method comprising thesteps of: (A) inserting into the body of the subject a guidewire thathas i) a distal portion, ii) a sensor positioned on or in the distalportion , ii) a proximal portion and iv) first electrical contactslocated on the proximal portion, said first electrical contacts beingconnected to the sensor; (B) inserting the proximal portion of theguidewire into a connector hub that has second electrical contacts suchthat the second electrical contacts of the connector hub becomeelectrically coupled to the first electrical contacts of the guidewire;(C) passing electrical energy through the sensor to cause the sensor toemit a field; and (D) using the image guidance system to determine thelocation of the field emitted by the sensor and to correlate saidlocation to stored anatomical image data, thereby ascertaining thelocation of the guidewire within the body. After the guidewire has beenplaced In an intended position within the body, the connector hub isremoved and a second device (e.g., a catheter) is advanced over theguidewire. Such second device is then used to perform a therapeutic ordiagnostic task within the subject's body.

Further aspects, details and embodiments of the present invention willbe understood by those of skill in the art upon reading the followingdetailed description of the invention and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a guidewire of one embodiment of the present inventionbeing used in conjunction with an IGS system to perform a transnasalprocedure.

FIG. 2 is a longitudinal sectional view of one embodiment of a guidewireof the present invention.

FIG. 2A is a cross sectional view through line 2A-2A of FIG. 2.

FIG. 2B is a cross sectional view through line 2B-2B of FIG. 2.

FIG. 2C is a cross sectional view through line 2C-2C of FIG. 2.

FIG. 3 is a side view of one embodiment of a sensor housing of theguidewire of FIG. 2.

FIG. 3A is a perspective view of a sensor assembly comprising the sensorhousing of FIG. 3 with an electromagnetic sensor coil and relatedpackaging mounted therein.

FIG. 4 is a longitudinal sectional view of a proximal hub device that isattachable to and detachable from the proximal end of a sensor-equippedguidewire of the present invention.

FIG. 4A is a longitudinal sectional view of the proximal hub device ofFIG. 4 attached to the guidewire of FIG. 2.

DETAILED DESCRIPTION

The following detailed description, the drawings and the above-set-forthBrief Description of the Drawings are intended to describe some, but notnecessarily all, examples or embodiments of the invention. The contentsof this detailed description, the accompanying drawings and theabove-set-forth brief descriptions of the drawings do not limit thescope of the invention or the scope of the following claims, in any way.

System Useable For Transnasal Image-Guided Procedures

With reference to FIG. 1, there is shown a guidewire 10 of the presentinvention inserted through a transnasal guide catheter 14 Into the noseof a subject. A connector hub 12 of the present invention is disposed onthe proximal end of the guidewire 10. The connector hub is connected bya cable 100 to an image guidance system 16. This image guidance systemgenerally includes a video monitor 18 and a computer 20. The manner inwhich these components of the system operate will be discussed infurther detail herebelow.

Guidewire Device

The guidewire device 10, and certain components thereof, are shown indetail in FIGS. 2-3A. In the particular embodiment shown, the guidewire10 comprises a flexible outer coil 49 having a core wire system 50extending therethrough. This guidewire 10 includes a distal portion 30,a mid-portion 32 and a proximal portion 34. In general, the outer coil49 is a flexible structure and the core wire system 50 serves to impartcolumn strength (e.g., “pushability”), torquability, and regionallyvarying degrees of rigidity to the guidewire 10.

In an embodiment suitable for certain transnasal applications, the outercoil 49 may be formed of stainless steel wire or other alloys 56 ofapproximately 0.005 to 0.007 inches diameter, disposed in a tighthelical coil so as to form a tubular structure that has a lumen 58 (asshown in FIG. 2B) and has an outer diameter of approximately 0.035inches. The core wire system 50 extends through lumen 58 of helicalouter coil 49 and a sensor assembly 60 (shown In detail in FIG. 3A) ismounted within the distal end of lumen 58, as explained fully herebelow.

The core wire system 50 comprises a distal core wire segment 50 d, aproximal core wire segment 50 p and a transitional core wire segment 50t. The proximal core wire segment 50 p is affixed (e.g., soldered orotherwise attached) to the outer coil 49 at locations L (FIG. 2). Inthis particular example, the distal core wire segment 50 d isapproximately two to approximately four centimeters in length and isformed of stainless steel wire having an outer diameter of approximately0.006 to approximately 0.008 inches and its distal portion mayoptionally be swaged or compressed to a generally flattenedconfiguration, thereby rendering that distal portion more flexible inone plane (e.g., up and down) than in the opposite plane (e.g., side toside), in accordance with techniques known in the art of guidewiremanufacture. The proximal end of distal core wire segment 50 d is round(i.e., not swaged or flattened) and is integral with the distal end ofthe transitional core wire segment 50 t, In this example, thetransitional core wire segment 50 t comprises a tapered region on thedistal end of proximal wire segment 50 p. The proximal core wire segment50 p is formed of stainless steel wire having an outer diameter ofapproximately 0.010 to approximately 0.013 inches and the transitionalcore wire segment 50 t tapers from the approximately 0.010 toapproximately 0.013 inch diameter at its proximal end to theapproximately 0.006 to approximately 0.008 inch diameter at its distalend where it attaches to the distal core wire segment 50 d. Since thedistal core wire segment 50 d is smaller in cross sectional dimensionthan the proximal core wire segment 50 d, the distal portion 30 of theguidewire 10 is more flexible than the mid-portion 32.

The sensor assembly 60 is mounted within the distal portion 30 of theguidewire. The sensor assembly 60 comprises a housing 62 that is lasercut from thin walled tubing made of stainless steel or other alloy. Thehousing 62 is cut to form a helical side wall 42 and a cylindricaldistal part 40. An electromagnetic coil 71 (FIG. 2A) is affixed byadhesive (e.g., epoxy), melted polymer or a combination of these withinthe housing 62, and lead wires 70 extend from the electromagnetic coil71, out of the proximal end of the sensor housing 62, as seen in FIG.3A. After the electromagnetic coil has been placed and secured withinthe sensor housing 62, an end plug 44 is inserted into the distal part40 of the sensor housing 62.

The sensor assembly 60 us then screwed into the distal end of the outercoil 49 causing the helical side wall 42 of sensor housing 62 to becomefrictionally engaged with adjacent convolutions of the outer coil 49.

The lead wires 70 a and 70 b pass through the lumen 58 of outer coil 49into the proximal portion 34 where they are connected to contacts 80 aand 80 b respectively. Contacts 80 a and 80 b comprise bands ofelectrically conductive material that extends around coil 49, as seen inFIGS. 2 and 2C. Insulators 82 (e.g., bushings formed of electricallyinsulating material such as PEBAX, adhesive, polyimide or a combinationof these) are disposed on either side of each contact 80 a, 80 b. Aproximal seal member 88 is disposed at the proximal end of the guidewire10 and the proximal end of the proximal core wire segment 50 p isreceived within such seal member 88.

The proximal portion 34 of the guidewire 10 is configured to he insertedInto the connector hub 14. The guidewire distal of the electricalcontacts can be coated with parylene, Teflon or silicone.

Connector Hub Device

One possible example of the construction of connector hub 14 is shown inFIGS. 4 and 4A. This embodiment of the connector hub 14 comprises amolded plastic housing 90 having an opening 92 in its distal end.Although not shown in the drawing, a retaining mechanism such as a twistlock Tuohy-Borst silicone valve grip mechanism can be located in opening92. Such a mechanism can be used to selectively grip the guidewire. Theopening 92 leads to a guidewire receiving recess 94 having first andsecond spring electrodes 96 a, 96 b disposed at spaced apart locationsthat correspond to the linear distance between the midpoints of contacts80 a, 80 b of the guidewire 10. Wires 98 connect spring electrodes 96 a,96 b to cable 100.

The guidewire receiving recess 94 terminates at its proximal end in anabutment surface 101. As seen in FIG. 4A, the proximal portion 34 ofguidewire 10 is inserted through opening 92 and is advanced into recess94 until the proximal end of the guidewire abuts against abutmentsurface 101, at which point, spring electrode 96 a will be touchingcontact 80 a and spring electrode 96 b will be touching contact 80 b.With the guidewire so inserted within connector hub 14 and cable 100connected to the image guidance system, electrical energy from the imageguidance system 16 is delivered to the electromagnetic coil 71 mountedin the distal portion 30 of guidewire 10. This enables real timetracking of the location of the guidewire's distal portion 30 within thesubject's body.

After the guidewire 10 has been navigated (whether with the aid of aguide 14) to a specific position within the subject's body, theconnector hub 14 may be removed from the proximal end of the guidewireand a device (e. g., a balloon catheter, lavage catheter, endoscope orvarious other working devices) may then be advanced over the guidewire.

In some embodiments, an outer layer 84 may be selectively disposed on aportion of the guidewire 10 to facilitate gripping and rotating of theguidewire by an operator's gloved hand. In the embodiment shown, thisouter layer 84 extends over a proximal segment (e.g., approximately 15centimeters) of the mid-portion 32 of outer coil 49. When so positioned,the outer layer 84 will be positioned on only the part of the guidewirethat is typically grasped by the operator during use. Thus, this outerlayer 84 does not impart additional rigidity to other regions of theguidewire 10. This is particularly useful in applications, such as thetransnasal application shown in FIG. 1, where the guidewire 10 extendson an upward angle as it exits the body. In such cases, added rigiditywill cause the guidewire to protrude more in the upward direction ratherthan curving downwardly so as to be more easily handled by the operator.

It is to be appreciated that the specific embodiment shown in thedrawings is merely one example of how the guidewire 10 and connector hub14 may be constructed. Many other variations are possible. For example,in some other embodiments, the outer coil 49 of the guidewire 10 may notextend over the mid-portion 32. Rather, the mid-portion 32 may beconstructed of a core wire within a cable wire tube, a polymeroverlamination, a hypotube, a braided polymer tube, or a helical coil.

It is to be further appreciated that the invention has been describedhereabove with reference to certain examples or embodiments of theinvention but that various additions, deletions, alterations andmodifications may be made to those examples and embodiments withoutdeparting from the intended spirit and scope of the invention. Forexample, any element or attribute of one embodiment or example may beincorporated into or used with another embodiment or example, unless todo so would render the embodiment or example unsuitable for its intendeduse. All reasonable additions, deletions, modifications and alterationsare to be considered equivalents of the described examples andembodiments and are to be included within the scope of the followingclaims.

1.-20. (canceled)
 21. A method of navigating a guidewire within a headof a patient, the method comprising: (a) inserting a distal end of aguidewire through a nose of a head of a patient to thereby position thedistal end within the nasal cavity of the patient, wherein the distalend includes a sensor; (b) generating an electromagnetic field, whereinthe head of the patient is positioned within the electromagnetic field;(c) tracking the position of the distal end of the guidewire within thenasal cavity of the patient, in the electromagnetic field, via thesensor in real time; and (d) advancing an instrument along the guidewireto perform an operation within the nasal cavity of the patient, based onthe tracked position of the distal end of the guidewire within the nasalcavity of the patient.
 22. The method of claim 21, wherein the act oftracking the position of the distal end of the guidewire within thenasal cavity of the patient comprises using an image-guided surgerysystem, wherein the sensor is in communication with the image-guidedsurgery system.
 23. The method of claim 22, wherein the act of trackingthe position of the distal end of the guidewire within the nasal cavityof the patient further comprises correlating location data associatedwith the distal end of the guidewire with at least one preoperativelyobtained image.
 24. The method of claim 23, wherein the at least onepreoperatively obtained image comprises a digital tomographic scan. 25.The method of claim 23, wherein the at least one preoperatively obtainedimage comprises a CT scan.
 26. The method of claim 23, wherein the atleast one preoperatively obtained image comprises an MRI scan.
 27. Themethod of claim 23, wherein the act of tracking the position of thedistal end of the guidewire within the nasal cavity of the patientfurther comprises superimposing a location of the distal end of theguidewire on at least one preoperatively obtained image.
 28. The methodof claim 27, wherein the act of superimposing a location of the distalend of the guidewire on at least one preoperatively obtained imagecomprises displaying at least one preoperatively obtained image of atleast a portion of the patient's head with a superimposed indicatorshowing the real time position of the distal end of the guidewire withinthe patient's head.
 29. The method of claim 22, further comprisingcoupling a proximal end of the guidewire with the image-guided surgerysystem to thereby provide a pathway for communication between the sensorand the image-guided surgery system.
 30. The method of claim 29, furthercomprising decoupling the proximal end of the guidewire from theimage-guided surgery system, wherein the act of advancing the instrumentalong the guidewire is performed after the act of decoupling theproximal end of the guidewire from the image-guided surgery system. 31.The method of claim 21, wherein the instrument comprises a dilationcatheter, wherein the act of advancing the instrument along theguidewire comprises advancing the dilation catheter to position adilator of the dilation catheter into a drainage passageway associatedwith a paranasal sinus.
 32. The method of claim 31, further comprisingdilating the advanced dilator to dilate the drainage passagewayassociated with the paranasal sinus.
 33. The method of claim 32, whereinthe dilator comprises a balloon, wherein the act of dilating theadvanced dilator comprises inflating the balloon.
 34. The method ofclaim 32, wherein the drainage passageway comprises a paranasal sinusostium.
 35. The method of claim 21, wherein the sensor comprises a coil36. The method of claim 35, wherein the act of generating theelectromagnetic field is performed via the coil.
 37. The method of claim21, further comprising inserting a guide into the nasal cavity of thepatient, wherein the act of inserting the distal end of the guidewirethrough the nose of the head of the patient is performed via the guide.38. The method of claim 37, wherein the guide comprises a tube, whereinthe guidewire is slidably disposed within the tube.
 39. A method ofnavigating a guidewire within a head of a patient, the methodcomprising: (a) inserting a distal end of a guidewire through a nose ofa head of a patient to thereby position the distal end within the nasalcavity of the patient, wherein the distal end includes a sensor; (b)activating an image guidance system, wherein the sensor is incommunication with the image guidance system; (c) tracking the positionof the distal end of the guidewire within the nasal cavity of thepatient via the sensor and the image guidance system in real time; (d)passing the distal end of the guidewire into a drainage passagewayassociated with a paranasal sinus in the head of the patient based onthe real time tracking via the sensor and the image guidance system; (e)advancing a dilation instrument along the guidewire to position adilator of the dilation instrument in the drainage passageway; and (F)expanding the dilator to thereby dilate the drainage passageway.
 40. Amethod of navigating a guidewire within a head of a patient, the methodcomprising: (a) inserting a guide member through a nose of a head of apatient to thereby position a distal end of the guide member within thenasal cavity of the patient; (b) advancing a guidewire along the guidemember to thereby position a distal end of the guidewire within thenasal cavity of the patient, wherein the distal end includes a sensor;(c) activating an image guidance system, wherein the sensor is incommunication with the image guidance system; (d) tracking the positionof the distal end of the guidewire within the nasal cavity of thepatient via the sensor and the image guidance system in real time; (e)passing the distal end of the guidewire into a drainage passagewayassociated with a paranasal sinus in the head of the patient based onthe real time tracking via the sensor and the image guidance system; (F)advancing a dilation instrument along the guidewire to position adilator of the dilation instrument in the drainage passageway; and (g)expanding the dilator to thereby dilate the drainage passageway.